The present invention is directed to a gas turbine engine assembly of a type capable of operating at elevated temperatures. In particular, the present invention is directed to a method of creating a single cooling circuit for thermally isolating the turbine housing from high temperatures that would otherwise adversely impact the delivery of cooling air/oil through the high temperature gas path to cool bearings, seals, nozzles and other engine components as well as maintaining the housing structural integrity.
Recent advances in turbine engine technology utilize ceramic combustor technology which can operate at temperatures exceeding even 2500xc2x0 F. It is essential that some housings must be cooled effectively and efficiently. Cooling the engine components while maintaining and even increasing engine efficiency and power are possible by operating at such higher temperatures without compromising the system.
Typically, such high temperature gas turbine engines require many complex cooling circuits to isolate the housing from high temperature gases. Separate cooling circuits are often utilized to cool the gas path liner and air/oil passages extending through the struts as required for lubrication of bearings, seals, turbine blades and associated engine components.
To insure adequate cooling, engine assemblies currently may utilize a circular inner hub and outer housing or shroud joined by a number of radially-extending support struts passing through the hot gas flow path. The struts may have hollow core areas extending lengthwise through the core for delivering air/oil to cool the bearings, nozzles and other components. The design of such inner hubs may accommodate bearings and various seal arrangements, while the outer shroud supports other ancillaries. The separate cooling circuits required for such shroud and hub assemblies are complex and expensive to fabricate and maintain.
There clearly is a need for an apparatus and method of creating a single cooling circuit which is simply supported within the engine compartment and capable of successfully isolating the engine housing from the high temperatures created by the gas combustion process, thereby enabling the housing to deliver cooling air to the bearings, seals, nozzles and other engine components. As will be explained, the present invention provides a method of fabricating an apparatus and system for achieving a thermally isolated gas turbine engine housing assembly.
In one aspect of the present invention, a method is disclosed for thermally isolating a turbine engine housing from high temperatures created by combustion gases flowing through the engine housing. The method includes the step of forming a floating liner assembly with a plurality of openings extending there through and forming an outer baffle assembly with a plurality of openings extending there through. The method further includes the step of forming an inner baffle assembly with a plurality of openings extending there through. The method includes the step of arranging the floating liner assembly, the outer baffle assembly and the inner baffle assembly in the turbine engine housing to form a single passageway for conveying a stream of compressed, cooling air against surfaces of the floating liner to collect heat from the floating liner and expel the heat into the stream of combustion gases flowing through the turbine engine housing.
In another aspect of the invention, a method is disclosed for fabricating an apparatus for thermally isolating a gas turbine engine housing having an outer ring-shaped housing member and an inner hub attached by housing struts from high temperatures created by combustion gases flowing through the turbine engine. The method comprises the step of positioning a floating liner assembly between the inner hub and the outer ring-shaped housing member and arranging a plurality of liner struts to enclose the housing struts, with a plurality of openings extending through the floating liner. The method includes the further step of positioning an outer baffle assembly about the floating liner assembly, with a plurality of openings extending through portions of the outer baffle assembly and the step of positioning an inner baffle assembly within the floating liner assembly, with a plurality of openings extending through portions the inner baffle. Finally, the method creates a single, continuous passageway for delivering pressurized air through openings in the outer ring-shaped housing member that impacts and flows through the openings in the outer baffle assembly, the floating liner assembly, the liner struts and the inner baffle assembly for collecting heat from the floating liner and expelling the heat to a stream of combustion gases flowing through the gas turbine engine.
In a yet further aspect of the present invention, a method is disclosed for thermally isolating a gas turbine outer ring-shaped housing member from high temperatures created by combustion gases flowing through the turbine engine. The method comprises the steps of positioning a floating liner assembly between an inner hub and the outer ring-shaped housing member and forming the floating liner assembly from separate, inner and outer ring-shaped liner members, having a number of openings, forming a cooling air passageway around each of the floating liner members and positioning an outer baffle assembly having two similar, generally cylindrically-shaped members to surround the floating liner outer ring-shaped member, and forming the outer baffle assembly with a plurality of through openings. The method further comprises the step of positioning an inner baffle assembly having two similar, generally cylindrically-shaped members within the floating liner inner ring-shaped member, and forming the inner baffle assembly with a plurality of openings extending through each outer baffle member. Finally, the method creates a single, continuous passageway for delivering pressurized air through openings in the outer ring-shaped housing member that impacts and flows through the openings in the outer baffle assembly, the floating liner assembly, the liner struts and the inner baffle assembly for collecting heat from the floating liner and expelling the heat to a stream of combustion gases flowing through the gas turbine engine.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.